Support for BigInt for Long columns?

[saibotsivad]

Looking through the code, I see intColumn which says "use to insert LONG" but, unless I'm missing something, we need to use BigInt to support LONG columns:

-   intColumn(name: string, value: number): Sender {
+   intColumn(name: string, value: bigint): Sender {

I dug far enough that I believe I could put a PR together, but wanted to make sure I wasn't missing something.